1. Field of the Invention
The present invention relates generally to microfluidics, and specifically to a high-throughput, label-free measurement of nano- and micro-particles suspended in a fluid.
2. Description of the Related Art
Counting and measuring particles suspended in a conducting fluid has been taking place in biomedical applications for almost fifty years. A resistive pulse technique has been used to size and count microparticles suspended in conducting fluid since Coulter first patented such in U.S. Pat. No. 2,656,508, which is herein incorporated by reference. Many incremental improvements to this original concept have been used since, and include modifications of the approach in order to achieve nanoparticle (dia. <1 micrometer) detection and measurement.
Of these improvements, two approaches seem to have provided promising results. The first, set forth in U.S. Pat. No. 7,279,883, which is incorporated by reference herein, uses a four-wire sensing technique, which is inherently limited in bandwidth by the current-sensing capabilities of the electronics.
The second approach, described in Leif et al. (Clin. Chem. 8:853 (1973); J. Histo. Chem. 22:626 (1974), J. Histo. Chem. 27:225 (1979)), which is incorporated by reference herein, describe the use of a fluidic voltage divider for the detection of microparticles (dia. >1 micrometer) and cells. These instruments are not nanofabricated, and are instead very complex, three-dimensional large structures which are costly to fabricate and operate.
It can be seen, then, that there is a need in the art for a non-bandwidth-limited system to measure and detect micro- and nanoparticles in fluid. It can also be seen that there is a need in the art for systems and devices that can measure and detect micro- and nanoparticles, systems and devices that are easier to fabricate and operate than those currently available.